1. Field of the Invention
The present invention relates to a method for testing energy efficiency of a display device and, more particularly, to a method for testing energy efficiency about on-mode average power consumption of a display device having an automatic brightness control (ABC) function.
2. Description of the Prior Art
Display devices, for example televisions, are widely used electrical appliances. To enhance the energy efficiency of display devices is good for energy saving and carbon emission reduction. U.S. Energy Star program, Taiwan Energy Label program, etc., provide energy efficiency specifications for televisions and methods for testing energy efficiency thereof. The energy efficiency specification of the television generally includes on-mode average power consumption and standby-passive mode average power consumption. Taking Energy Star program as an example, the on-mode average power consumption of the television shall be less than or equal to the maximum allowable on-mode average power consumption PON_MAX given byPON_MAX=78.5×tanh[0.0005×(A−140)+0.038]+14,where PON_MAX is in watts (W), and A is the viewable screen area of the television in square inches. The standby-passive mode average power consumption of the television shall be less than or equal to 0.5 W.
Taking the television having the ABC function as an example, a method for testing energy efficiency about on-mode average power consumption thereof includes: turning on the television and enabling the ABC function to activate an ambient light sensor; after the television reaches a steady state, playing a test video on television, and then using a light source to respectively simulate ambient light levels of 3, 12, 35, and 100 lux incident to the ambient light sensor for a test time of 10 minutes to respectively measure power consumptions P3, P12, P35, and P100; and, calculating the on-mode average power consumption PON=(P3+P12+P35+P100)/4. It takes more than 40 minutes to perform the testing process once. Moreover, when the on-mode average power consumption PON is greater than the maximum allowable on-mode average power consumption PON_MAX, meaning that the testing result fails to meet the specification requirement, so settings (e.g. brightness adjustment ratios corresponding to the ambient light levels) of the television need to be adjusted, and then the above testing process is repeatedly performed until the testing result meets the specification requirement. Obviously, the conventional method for testing energy efficiency about the on-mode average power consumption of the television takes too much time.